I have been working on bringing a 1998 916 back to life after the previous owner started parting her out. This past weekend was the first time that I was able to take her on a couple of good rides and all I can think about is the next ride. However I am running into a problem after I roll off the throttle and then come back on with slight throttle it will sputter, this is usually under 4000 rpms and have noticed it coming off idle. It seems like if I come on with more throttle it doesnt seem to sputter. The interesting thing is that my buddy with a 05 Monster S4 has similar symptoms. Part of me wonders if it is just a characteristic of these motorcycles and is an issue that requires me to adjust my riding style. Ideally I would like to try and figure out the root of the problem and fix it. I know there has been a lot of discussion of installing a power commander and custom dyno tuning but I am wondering if I am missing something in my setup.
The history on the bike is that it came a Termignoni exhaust but without a computer so I replaced it with a unit from Gotham Cycles and a FIM chip. So I was really started from square one setting up the throttle position sensor and then moved to a throttle body sync. When it came time for the air bypass screw to set the idle to 1100 rpm, as described in the manual, it seemed like no matter what I did, no adjustment would effect the idle. In order to get the idle smooth I had to screw in the idle screw, what the manual says should be at ~310 mv reading from the throttle position sensor. Also when it came to setting the CO trim pot, I didn't have access to a exhaust gas analyzer so I had to roughly set it. It was initially running lean but after an adjustment it seemed to be running well and I am about right in the middle of the adjustment.
At this point I have the air bypass screw set to 1/4 turn from full closed and the idle set to 1200 rpm with the idle screw. It seems like it is almost running lean on really small throttle which from what I understand is controlled by the air bypass screw. Should I have the air bypass screw fully closed? How many turns do most people have on their setups? Is it ok to have the idle screw set the idle as it seems like the only way it will be stable? I have also played with small CO trim pot adjustments to see if it would effect it but the sputter was always there. I am open to any ideas or feedback.
Thanks,
David
The history on the bike is that it came a Termignoni exhaust but without a computer so I replaced it with a unit from Gotham Cycles and a FIM chip. So I was really started from square one setting up the throttle position sensor and then moved to a throttle body sync. When it came time for the air bypass screw to set the idle to 1100 rpm, as described in the manual, it seemed like no matter what I did, no adjustment would effect the idle. In order to get the idle smooth I had to screw in the idle screw, what the manual says should be at ~310 mv reading from the throttle position sensor. Also when it came to setting the CO trim pot, I didn't have access to a exhaust gas analyzer so I had to roughly set it. It was initially running lean but after an adjustment it seemed to be running well and I am about right in the middle of the adjustment.
At this point I have the air bypass screw set to 1/4 turn from full closed and the idle set to 1200 rpm with the idle screw. It seems like it is almost running lean on really small throttle which from what I understand is controlled by the air bypass screw. Should I have the air bypass screw fully closed? How many turns do most people have on their setups? Is it ok to have the idle screw set the idle as it seems like the only way it will be stable? I have also played with small CO trim pot adjustments to see if it would effect it but the sputter was always there. I am open to any ideas or feedback.
Thanks,
David